Faith is one of those words that is hard to pin down what it means. Does it mean hope? Well Paul listed hope as a separate thing in Corinthians from faith, although he does list them together as though having certain things in common. Does it mean belief; but belief in what? Is it belief in a person or the claim of the existence of the supernatural or metaphysical world? I can believe that other humans exist but I might not trust their motives if I knew some of them. In some ways the only thing anyone can absolutely know is that ‘I think therefor I am`. One’s own consciousness! Yet we have people in the world trying to convince some that even that is only an illusion, or that our own consciousness is real but all else could be an illusion, as it the matrix type of world view. This whole subject really gets into deep issues.
Some people who tell us that the physical senses are the only guide to truth will also say that consciousness is an illusion, however as a result of that they are really denying the concept of truth itself as a real thing, because truth is not a physical object and only exists in the abstract if real, which they tell us does not exist. It sometimes gets even worse than that, because even the evidence of the senses is said to be fallible and untrustworthy. Often this argument of untrustworthy senses is used to cast doubt on those who claim supernatural experience, or the witnessing it via their senses. However the alternative explanation is a materialist scientific world view, but this too is derived from those same infallible senses which would cast that into doubt in the same way. This criticism however is not accepted as valid by the materialist position because of the mathematical consistency of such physical theories with mathematics, as well as such theories internal consistency with themselves and other theories. The problem with this rejection is that mathematics itself does not exist in the real world, as its domain is that of the mind only. Also the apparent internal consistency of a theory with itself is only ever understood as consistent in the mind of understanding, as is all understanding whatsoever. One needs consciousness to have a mind that can understand what the mind is doing. Yet the materialist position, if held to be universally true says that the mind is itself only physical, thus an illusion.
So what is faith? I’m not totally sure but everyone seems to have it weather atheist or not.